docs: def to_bool(value):
      '''
      Transform a value into a boolean with the following rules:
  
      - a boolean is returned untouched
      - a string value should match any casinf of 'true' to be True
      - an integer should be superior to zero to be True
      - all other values are False
      '''
      if isinstance(value, bool):
          return value
      elif isinstance(value, basestring):
          return value.lower() == 'true' or value.lower() == 't'
      elif isinstance(value, int):
          return value > 0
      else:
          return False